Many people with significant physical or cognitive disabilities use a switch to access their computer and navigate websites. A switch is a simple device like a button that is either on or off. There are many types of switch used by people with disabilities. A switch can be operated by any part of the body that has voluntary muscle control. The action a user performs to activate a switch will obviously therefore affect the choice of switch used.
Types of switch include; Sensor switch, Foot Switch, Buddy Button, Joggle Switch, Micro Light, Chin Switch and Sip and Puff.
As stated earlier all switches perform the same action so the only variation is in the force needed or technique used to activate it. Many people who are unfamiliar with the techniques employed find it hard to imagine how someone can control something as complex as a computer using such a basic means of inputting information.
In terms of computer access or access to more complex devices a switch in itself can’t do much, it needs the addition of a USB or Bluetooth adapter (for a computer or tablet) and a scanning. The JoyCable is the simplest USB switch interface on the market; it will allow you to connect two switches to the computer and can be used with many of the more popular switch access programs without a driver.
It is through it’s use with Scanning software that a switch can perform the actions of a keyboard and mouse. There are many options when it comes to choosing scanning software but techniques used are usually the same. Switch access scanning is an indirect selection technique that is used to choose items from the selection set. The user can only make selections when the scanning indicator (usually a change of colour although an auditory signal can be used also) is on the desired choice. The scanning indicator moves through items by highlighting each item on the screen (i.e., visual scanning), or by announcing each item via voice output (i.e., auditory scanning), and then the user activates a switch to select the item.
- There is a good interactive scanning tutorial here that demonstrates the techniques used.
Different techniques of mouse emulation are used, some as simple as four arrows and a button for click, right click and double click. Other more effective approaches are the horizontal/vertical scanning and Radar scanning. In horizontal/vertical scanning a horizontal line appears at the top of the screen and then starts to move slowly downwards. When it reaches the level of the target the user activates the switch. Then the cursor begins to move along this line from left to right until the target is reached and the user activates the switch again. The radar technique is similar but this time the line is radial and circles around the centre of the screen until the switch is activated. As you can imagine inputting data for a switch user is time consuming and laborious.
Different scanning techniques (group scanning) and a “frequency of use” layout of the interface can improve efficiency but it is still difficult.
Types of Switch Access Software
- The Grid 2: This software is a powerful communication, computer access and environmental control solution that can be customised to the users needs and ability.
- SwitchXS: SwitchXS provides virtually complete access to Mac OS X and all standard Mac applications for people who can only use one or more switches. It offers full mouse and keyboard emulation by means of a so-called scanning mode.
- CrossScanner: CrossScanner by RJ Cooper is a universal way to run software by 1 or 2 switch(es). With the switch(es) plugged into any switch interface , the user is able to perform mouse moves and clicks, double clicks, drags, operate menu’s and even enter text (with optional OnScreen keyboard).
Low Cost Options
There are many free open source applications that enable switch users to access their computer and the internet. OATS (Open Source Assistive Technology Software) is a good resource for switch access software as it is for a wide variety of Assistive Technology software.
- SAW (Special Access to Windows): SAW replaces the mouse and keyboard with a series of onscreen Selection Sets – arrangements of letters, words, symbols, numbers and shapes that can be automatically or manually scanned, item by item, and selected using switches. You can write, draw, move the cursor around the screen – SAW5 gives you the access power to all aspects of operation.
- StealthSwitchII: Cheaper mainstream alternative to the Crick switch box.
- Switch access software